(a) Overall objectives: these are to investigate the function of vitamin A by means of a study of the mechanism whereby this vitamin affects the synthesis of glycoproteins in corneal epithelium; (b) objectives for the current year: to isolate the glycoprotein stimulated in its synthesis by incubation of corneas with retinol in its native state and to determine its character: is it a mucin, secreted into the medium, or a membrane glycoprotein synthesized intracellularly? How does it relate to the glycoprotein, the synthesis of which is inhibited in vitro. A deficiency? What are the exact conditions of stimulation and how are they affected by protein and RNA synthesis inhibitors? Can retinyl phosphate and retinyl glycophospholipids, made in our laboratory, also stimulate corneal glycoprotein synthesis in vitro?